The Hoopak can be found in Dragonlance: Shadow of the Dragon Queen, page 188.
This magic weapon grants a +1 bonus to attack and damage rolls made with it. While holding it, you can take a Bonus Action to cause it to shed Bright Light in a 30-foot radius and Dim Light for an additional 30 feet. You can extinguish the light as a Bonus Action.
The weapon has 4 charges. You can take a Reaction immediately after being hit by an attack roll to expend 1 of the weapon's charges and force the attacker to make a DC 15 Constitution saving throw. On a failed save, the attacker has the Blinded condition until the end of its next turn. The weapon regains 1d4 expended charges daily at dawn.
A hoopak is a sturdy stick with a sling at one end and a pointed tip at the other.
When you make a melee attack with this weapon, you ignore its ammunition property. You can use the hoopak as a martial ranged weapon. If you do, it uses the ammunition property, uses sling bullets, and deals 1d4 bludgeoning damage on a hit.
You can use a weapon that has the ammunition property to make a ranged attack only if you have ammunition to fire from the weapon. Each time you attack with the weapon, you expend one piece of ammunition. Drawing the ammunition from a quiver, case, or other container is part of the attack. Loading a one-handed weapon requires a free hand. At the end of the battle, you can recover half your expended ammunition by taking a minute to search the battlefield.
If you use a weapon that has the ammunition property to make a melee attack, you treat the weapon as an improvised weapon. A sling must be loaded to deal any damage when used in this way.
When making an attack with a finesse weapon, you use your choice of your Strength or Dexterity modifier for the attack and damage rolls. You must use the same modifier for both rolls.
This weapon requires two hands to use. This property is relevant only when you attack with the weapon, not when you simply hold it.